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Biomedical subjects

S N Reske

Publications and source records attributed to S N Reske.

125 records · Page 7Linked to original sources
PubMed1985

Captopril mediated decrease of aortic regurgitation.

The effect of captopril mediated afterload reduction on aortic regurgitation was investigated in 10 patients. Regurgitation was quantitated by means of the regurgitation fraction and the relation of regurgitant volume to end diastolic volume. These variables were derived from gated radionuclide ventriculography. After captopril treatment the blood concentration of angiotensin I rose whereas that of angiotensin II fell significantly. The conversion of angiotensin I to II was reduced to about 50% of the control value. Whereas blood pressure and heart rate did not change significantly, the regurgitation fraction and the regurgitant volume, normalised to end diastolic volume, were significantly reduced by captopril treatment. The ejection fraction remained essentially unchanged. These findings suggest that captopril reduces aortic regurgitation by reducing afterload.

Angiotensin I↗
PubMed1985

[Localization of pre-excitation in the WPW syndrome by analysis of the ventricular contraction course].

Fourier phase analysis of gated radionuclide ventriculography (RNV) was applied in 23 patient for the identification of cardiac contraction patterns in WPW syndrome (controls with normal ventricular function and sinus rhythm, n = 30). The sequence and velocity of regional ventricular wall motion was determined and correlated to the results of electrophysiological studies. In 3/23 patients the contraction pattern was not different from controls. Indicating the preexcitation in 20/23 patients the earliest ventricular contraction was localized as follows: right atrial n = 5, paraseptal right n = 2, paraseptal left n = 6 and atrial left n = 7. In 15/16 patients nuclear data corresponded with electrophysiological endocardial mapping. Phase analysis of RNV provides a reliable non-invasive method for localization of preexcitation in WPW syndrome.

Electrocardiography↗
PubMed1984

[Reduction of regurgitation in aortic insufficiency by inhibition of the renin-angiotensin converting enzyme].

The effect of captopril-mediated afterload reduction on regurgitation was investigated in 10 patients with aortic insufficiency. Regurgitation was quantitated by the regurgitation fraction and the relation of regurgitant volume to enddiastolic volume, which were derived from gated radionuclide ventriculography. 19 patients with coronary artery disease and no evidence of valvular heart disease served as controls. In patients with coronary artery disease no significant regurgitation was found. In patients with aortic regurgitation the blood concentration of angiotensin I increased whereas that of angiotensin II decreased significantly after captopril-medication; thus, the conversion of angiotensin I to II was reduced to about 50% of the control value. Whereas blood pressure and heart rate did not change significantly, the regurgitation fraction and the normalized regurgitant volume were significantly reduced. The ejection fraction remained essentially unchanged. These findings suggest a favorable influence of captopril-induced afterload reduction on hemodynamics in aortic regurgitation.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1984

15(p-[123I]Iodophenyl)pentadecanoic acid as tracer of lipid metabolism: comparison with [1-14C]palmitic acid in murine tissues.

Uptake and turnover of 15-(p-[123I]iodophenyl)pentadecanoic acid (I-PPA), a radioiodinated free-fatty-acid analog, was examined in heart, lung, liver, kidneys, and spleen and compared with that of [1-14C]palmitic acid (PA). High cardiac uptake of both I-PPA (4.4% dose/g) and PA (2.8% dose/g) was followed by a two-component tracer clearance. Kinetics of I-PPA were linked to those of PA in tissues with primary oxidation of free fatty acids or their preferential storage. Tissue lipids of all organs investigated were labeled concordantly by both tracers. Fractional distributions of PA and I-PPA incorporation in tissue lipids were significantly correlated. Thus general pathways of FFA tissue metabolism are traced by this radioiodinated free-fatty-acid analog. High-quality metabolic imaging of the heart is possible by means of I-PPA with conventional scintigraphic equipment or cross-sectional imaging with single photon emission computerized tomography facilities.

Animals↗
PubMed1984

[Cause of crossed cerebellar diaschisis in cerebrovascular disease].

In 31 patients with completed stroke (n = 30) or PRIND (n = 1) a brain SPECT with 123I-labeled amphetamines was performed. In 14 (= 45%) of the respective patients--suffering from long-lasting hemiplegia--crossed cerebellar diaschisis was present. The interval between onset of the disease and time of examination varied between 1 week and 7 years. On the other hand, patients without crossed cerebellar diaschisis did not, with one exception, suffer from hemiplegia. It is likely that this phenomenon is caused by the reduction of spino-cerebellar stimuli due to the paresis of the respective extremities.

Adult↗
PubMed1984

Relation of myocardial blood flow and initial cardiac uptake of 15-(p-123I-phenyl)-pentadecanoic acid in the canine heart.

In 8 pentobarbital-anesthetized mongrel dogs the correlation between regional myocardial blood flow (RMBF) and regional cardiac uptake of 15-(p-123I-phenyl)-pentadecanoic acid (IPPA) was determined. Three animals were studied under control conditions, in three dogs an acute ischemia was produced by LAD ligation, and two dogs were paced at 195 beats/min. RMBF values were 20-50 ml/min X 100 g in acutely ischemic myocardium. 90-120 ml/min X 100 g under normal conditions and 200-250 ml/min X 100 g during pacing-induced stimulation. Total cardiac uptake of IPPA was 4.5-6% of the injected dose. In normal and acutely ischemic myocardium a good correlation between RMBF and IPPA uptake was obtained. Under stimulated conditions only a moderate increase of IPPA accumulation was found. At RMBF values above 150-170 ml/min X 100 g an upper limit of IPPA uptake was observed and can be explained by limited diffusion or an increased utilization of alternative substrates.

Animals↗
PubMed1984

Cardiac metabolism of omega-(p-iodo-phenyl)-pentadecanoic acid: a gas-liquid chromatographic-mass spectrometric analysis.

The omega-(p-iodo-phenyl)-pentadecanoic acid (I-PPA) has been used successfully for the investigation of the cardiac metabolic activity and for the imaging of the myocardium (Machulla, H. J., M. Marsmann, and K. Dutschka. 1980. Eur. J. Nucl. Med. 5: 171-173). In the present study, the metabolic fate of I-PPA in the perfused rat heart was investigated. After application of I-PPA to the perfused rat heart, lipids were extracted, separated by thin-layer chromatography, and transesterified. The gas-liquid chromatographic-mass spectrometric (GLC-MS) analysis yielded the following results. Heart triglycerides contained 73% of the recovered I-PPA; only small amounts of unesterified I-PPA were found in the heart. This finding is in good agreement with the radioactivity distribution determined simultaneously. Three metabolites could be detected and characterized by GLC-MS: omega-(p-iodo-phenyl)-propionic acid, omega-(p-iodo-phenyl)-propenoic acid, and p-iodo-benzoic acid. These short chain metabolites were found only in the perfusion medium demonstrating that they are not enriched but rapidly eliminated from the perfused rat heart.

Animals↗
PubMed1984

Cardiac metabolism of 15 (p-I-123 phenyl-) pentadecanoic acid after intracoronary tracer application.

Myocardial turnover of omega-(p123I-Phenyl-) pentadecanoic acid and release of its metabolites into the coronary sinus and peripheral blood has been studied in patients with coronary artery and valvular heart disease. After intracoronary tracer injection myocardial extraction fractions of 45-53% in control subjects were observed. In patients with coronary artery disease (CAD) normal to reduced values (34-61%) were established. Hydrophilic catabolites of I-PPA, probably p123I-benzoic and -hippuric acid as well as small amounts of the non-metabolized tracer were found in coronary sinus and peripheral blood. Myocardial tracer uptake and clearance patterns were clearly different in normal myocardium when compared to that obtained in patients with CAD. Thus, evaluation of myocardial I-PPA metabolism might provide a new diagnostic tool for assessment of integrity of the heart's muscular metabolic function.

Coronary Disease↗
PubMed1983

Radiolabeled DNase, a potential indicator for noninvasive detection of tissue damage.

Pancreatic DNase I was labeled with 131I or fluorescamine and injected IV into NMRI mice bearing a sarcoma 180. Of the injected tracer, 1.5%-2% was found to accumulate per g tumor. In sections of tumor tissue DNase was localized in damaged cells in solid and necrotic tumor regions. This binding is most probably due to specific interaction of DNase with actin, an ubiquitous cytoskeletal protein. Two-component blood clearance with a rapid first component (two-thirds of applied radioactivity) was observed. The labeled tumor could easily be visualized by gamma camera imaging. The findings suggest DNase to be a potent radiopharmaceutical for imaging damaged tissue, occurring in malignant tumors as well as in infarcts, and inflammatory lesions.

Animals↗
PubMed1982

[Experimental myocardial infarct in computerized tomography].

The findings on computer tomography after ligation of the coronary artery of a dogs heart are described. The ischaemic area can be differentiated from normal myocardium by its hypo-dense appearance. The localisation and size of the ischaemic area correlates with the scintigraphic findings. The known morphological and functional changes after intravenous oxyfedrin (positively inotropic, increased myocardial blood-flow) can also be seen on the computer tomogram (after oxyfedrin: myocardial thickening, reduction in cross-sectional area of the left ventricle, improved contraction, increased density of the ischaemic area). This confirms the possible diagnostic role of CT in the elucidation of changes in the left ventricle in the course of coronary disease.

Animals↗
PubMed1982

Assessment of regional myocardial uptake and metabolism of omega-(p-123I-phenyl) pentadecanoic acid with serial single-photon emission tomography.

The utility of myocardial imaging and assessment of regional myocardial metabolism of omega-(123I-paraphenyl-)pentadecanoic acid (I-PPA) by means of serial single-photon tomography is demonstrated in animal experiments. High quality cross sectional images of dog hearts with clear delineation of left ventricular walls are obtained. Myocardial infarcts are visualized as areas of deficient radioactivity uptake. I-PPA elimination from non-infarcted myocardial regions is significantly (p less than 0.001) prolonged when compared with unaffected controls. Hence, not only localized absence of uptake of free fatty acid by infarcted myocardium can be demonstrated with serial single-photon tomography but also general impairment of cardiac FFA-metabolism.

Animals↗
PubMed1982

[SPECT (201T1) of the myocardium after experimental infarction].

On the basis of an experimental model the extent was studied to which even small intramural myocardial ischemia can be demonstrated by SPECT. For this purpose ligature of the Ramus interventricularis anterior (n = 10) or of the Ramus circumflexus (n = 2) of the left coronary artery was performed in 12 dogs to produce myocardial lesions of the anterior and posterior wall. Transmission computed tomography (TCAT) served as a control method in 10 dogs showing that 6 lesions were transmural and 4 intramural. All infarctions could be detected by SPECT with a rotating gamma camera (TCAT: 9/10). TCAT after contrast media enhancement with its morphological advantages (high resolution) should, however, not be used in the acute phase of myocardial infarction because of its hemodynamic side effects. Thus, SPECT with 201T1 remains the method of choice even for the proof of minor intramural (acute) ischemic lesions.

Animals↗
PubMed1981

[Single-photon emission computed tomography (SPECT) of the liver with a rotating gamma camera system (author's transl)].

In a total of 202 patients conventional scintigraphy as well as emission computed tomography (SPECT) of the liver were performed. In 123 patients focal lesions could be excluded whereas in 30 cases the presence of liver tumors was verified. In 5 of the respective cases correct diagnosis was only possible by SPECT, in 9 further cases SPECT improved the diagnostic accuracy (topography, size and number of defects). In patients with normal findings of the liver, conventional scintigraphy yielded false-positive findings in 9 cases and SPECT in 7 cases. By combination of both methods the false-positive diagnoses could be reduced to 5. 48 patients had cirrhosis of the liver: in all of them conventional camera scintigraphy was superior to SPECT because of reduced activity accumulation in the liver (insufficient statistics).

Diagnosis, Differential↗
PubMed1981

In vivo assessment of phagocytic properties of Kupffer cells.

Three-compartment analysis was used to assess the kinetics of phagocytosis of Tc-99m-labeled human serum albumin microparticles (Tc-99m HSA-MM) in human Kupffer cells in vivo. The tracer turnover in these phagocytic cells could be described by a monoexponential accumulation with a two-stage elimination phase. Three-compartment analysis of the Tc-99m HSA-MM kinetics allowed us to quantify tracer attachment, phagocytosis, and degradation in Kupffer cells. The calculated time course of phagocytosis in ten control subjects proved to be identical to that of phagocytosis of various test substances in mouse macrophage monolayers (1). In addition, an impairment of particle turnover at the macrophage membrane, a significantly diminished (p less than 0.01) phagocytosis rate of the tracer, was observed in ten patients with various tumors.

Adult↗
PubMedDate not supplied

Experimental and clinical experience with iodine 123-labeled iodophenylpentadecanoic acid in cardiology.

Iodine 123-labeled iodophenylpentadecanoic acid (IPPA) has been synthesized for investigating myocardial free fatty acid (FFA) metabolism. The diagnostic application of labeled FFA in heart disease may be important, because FFA is the preferred substrate of cardiac energy metabolism at rest in the fasting state. In addition, regional myocardial FFA uptake and regional myocardial blood flow are tightly coupled in normal myocardium with beta-oxidation, which is extremely sensitive to oxygen deprivation. This article outlines basic physiologic pathways of cardiac IPPA metabolism in normal, acutely ischemic, and reperfused viable myocardium and summarizes the results of experimental studies in animals, validating the application of IPPA as an 123I-labeled fatty acid analog. In addition, the most important clinical studies indicating the clinical use of IPPA for diagnosis of coronary heart disease and myocardial viability are presented.

Animals↗